With the popularization of mobile phone use, a mobile phone user receives lots of information or calls in daily life, but when the mobile phone user is in a certain particular environment, the mobile phone user cannot process the received information or calls in time.
For example, when the mobile phone user is in some occasions that require silence such as in a meeting or in a library, the mobile phone user adjusts the mobile phone to be a meeting mode or a silent mode, so the mobile phone user cannot sense the received information or call; or when the mobile phone user is on a bus or in some noisy environments, the decibel of a mobile phone ringtone is not high enough to make the mobile phone user notice that the mobile phone receives a short message or a call, thereby missing some important short messages or calls.
For senders who make the calls or sends the information, they cannot process some important things because the other side cannot answer the phone or reply short messages in time.